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<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2011 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: WindowQueryList.html 689 2013-06-28 19:22:16Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.dellroad.stuff.vaadin;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>import java.util.Arrays;<a name="line.10"></a>
<span class="sourceLineNo">011</span>import java.util.List;<a name="line.11"></a>
<span class="sourceLineNo">012</span><a name="line.12"></a>
<span class="sourceLineNo">013</span>/**<a name="line.13"></a>
<span class="sourceLineNo">014</span> * {@link QueryList} implementation that only actually holds a portion, or "window" of a larger list.<a name="line.14"></a>
<span class="sourceLineNo">015</span> * If a list element outside the "window" is accessed, an {@link InvalidQueryListException} is thrown,<a name="line.15"></a>
<span class="sourceLineNo">016</span> * prompting another query.<a name="line.16"></a>
<span class="sourceLineNo">017</span> *<a name="line.17"></a>
<span class="sourceLineNo">018</span> * @see AbstractQueryContainer<a name="line.18"></a>
<span class="sourceLineNo">019</span> */<a name="line.19"></a>
<span class="sourceLineNo">020</span>public class WindowQueryList&lt;T&gt; implements QueryList&lt;T&gt; {<a name="line.20"></a>
<span class="sourceLineNo">021</span><a name="line.21"></a>
<span class="sourceLineNo">022</span>    private final List&lt;? extends T&gt; window;<a name="line.22"></a>
<span class="sourceLineNo">023</span>    private final long offset;<a name="line.23"></a>
<span class="sourceLineNo">024</span>    private final long totalSize;<a name="line.24"></a>
<span class="sourceLineNo">025</span><a name="line.25"></a>
<span class="sourceLineNo">026</span>    /**<a name="line.26"></a>
<span class="sourceLineNo">027</span>     * Constructor when the original list is given with window bounds.<a name="line.27"></a>
<span class="sourceLineNo">028</span>     *<a name="line.28"></a>
<span class="sourceLineNo">029</span>     * @param list original list from which to cache elements<a name="line.29"></a>
<span class="sourceLineNo">030</span>     * @param offset index in the list of the first element in the window<a name="line.30"></a>
<span class="sourceLineNo">031</span>     * @param count number of elements in the window<a name="line.31"></a>
<span class="sourceLineNo">032</span>     * @throws IllegalArgumentException if {@code list} is null<a name="line.32"></a>
<span class="sourceLineNo">033</span>     * @throws IllegalArgumentException if {@code offset} and/or {@code count} are invalid<a name="line.33"></a>
<span class="sourceLineNo">034</span>     */<a name="line.34"></a>
<span class="sourceLineNo">035</span>    @SuppressWarnings("unchecked")<a name="line.35"></a>
<span class="sourceLineNo">036</span>    public WindowQueryList(List&lt;? extends T&gt; list, int offset, int count) {<a name="line.36"></a>
<span class="sourceLineNo">037</span>        if (list == null)<a name="line.37"></a>
<span class="sourceLineNo">038</span>            throw new IllegalArgumentException("null list");<a name="line.38"></a>
<span class="sourceLineNo">039</span>        this.totalSize = list.size();<a name="line.39"></a>
<span class="sourceLineNo">040</span>        if (offset &lt; 0 || offset &gt; this.totalSize)<a name="line.40"></a>
<span class="sourceLineNo">041</span>            throw new IllegalArgumentException("bad offset");<a name="line.41"></a>
<span class="sourceLineNo">042</span>        this.offset = offset;<a name="line.42"></a>
<span class="sourceLineNo">043</span>        if (count &lt; 0 || offset + count &gt; this.totalSize)<a name="line.43"></a>
<span class="sourceLineNo">044</span>            throw new IllegalArgumentException("bad count");<a name="line.44"></a>
<span class="sourceLineNo">045</span><a name="line.45"></a>
<span class="sourceLineNo">046</span>        // Copy elements to allow original list to be freed<a name="line.46"></a>
<span class="sourceLineNo">047</span>        this.window = (List&lt;T&gt;)Arrays.asList(list.subList(offset, offset + count).toArray());<a name="line.47"></a>
<span class="sourceLineNo">048</span>    }<a name="line.48"></a>
<span class="sourceLineNo">049</span><a name="line.49"></a>
<span class="sourceLineNo">050</span>    /**<a name="line.50"></a>
<span class="sourceLineNo">051</span>     * Constructor when a "window" list is given with its position in the original list.<a name="line.51"></a>
<span class="sourceLineNo">052</span>     *<a name="line.52"></a>
<span class="sourceLineNo">053</span>     * @param window list of only those elements in the "window"<a name="line.53"></a>
<span class="sourceLineNo">054</span>     * @param offset offset of the "window" in the original list<a name="line.54"></a>
<span class="sourceLineNo">055</span>     * @param totalSize total size of the original list<a name="line.55"></a>
<span class="sourceLineNo">056</span>     * @throws IllegalArgumentException if {@code window} is null<a name="line.56"></a>
<span class="sourceLineNo">057</span>     * @throws IllegalArgumentException if &lt;code&gt;offset &amp;lt; 0&lt;/code&gt;<a name="line.57"></a>
<span class="sourceLineNo">058</span>     * @throws IllegalArgumentException if &lt;code&gt;offset + window.size() &amp;gt; totalSize&lt;/code&gt;<a name="line.58"></a>
<span class="sourceLineNo">059</span>     */<a name="line.59"></a>
<span class="sourceLineNo">060</span>    public WindowQueryList(long offset, List&lt;? extends T&gt; window, long totalSize) {<a name="line.60"></a>
<span class="sourceLineNo">061</span>        if (window == null)<a name="line.61"></a>
<span class="sourceLineNo">062</span>            throw new IllegalArgumentException("null window");<a name="line.62"></a>
<span class="sourceLineNo">063</span>        if (offset &lt; 0)<a name="line.63"></a>
<span class="sourceLineNo">064</span>            throw new IllegalArgumentException("offset &lt; 0");<a name="line.64"></a>
<span class="sourceLineNo">065</span>        if (offset + window.size() &gt; totalSize)<a name="line.65"></a>
<span class="sourceLineNo">066</span>            throw new IllegalArgumentException("offset + window.size() &gt; totalSize");<a name="line.66"></a>
<span class="sourceLineNo">067</span>        this.window = window;<a name="line.67"></a>
<span class="sourceLineNo">068</span>        this.offset = offset;<a name="line.68"></a>
<span class="sourceLineNo">069</span>        this.totalSize = totalSize;<a name="line.69"></a>
<span class="sourceLineNo">070</span>    }<a name="line.70"></a>
<span class="sourceLineNo">071</span><a name="line.71"></a>
<span class="sourceLineNo">072</span>    @Override<a name="line.72"></a>
<span class="sourceLineNo">073</span>    public long size() {<a name="line.73"></a>
<span class="sourceLineNo">074</span>        return this.totalSize;<a name="line.74"></a>
<span class="sourceLineNo">075</span>    }<a name="line.75"></a>
<span class="sourceLineNo">076</span><a name="line.76"></a>
<span class="sourceLineNo">077</span>    @Override<a name="line.77"></a>
<span class="sourceLineNo">078</span>    public T get(long index) throws InvalidQueryListException {<a name="line.78"></a>
<span class="sourceLineNo">079</span>        if (index &lt; 0 || index &gt;= this.totalSize)<a name="line.79"></a>
<span class="sourceLineNo">080</span>            throw new IndexOutOfBoundsException("index = " + index);<a name="line.80"></a>
<span class="sourceLineNo">081</span>        if (index &lt; this.offset || index &gt;= this.offset + this.window.size())<a name="line.81"></a>
<span class="sourceLineNo">082</span>            throw new InvalidQueryListException();<a name="line.82"></a>
<span class="sourceLineNo">083</span>        return this.window.get((int)(index - this.offset));<a name="line.83"></a>
<span class="sourceLineNo">084</span>    }<a name="line.84"></a>
<span class="sourceLineNo">085</span>}<a name="line.85"></a>
<span class="sourceLineNo">086</span><a name="line.86"></a>




























































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